Fluorescent lamp circuit and starting means therefor



1963 TAKIZO KOBAYASHI 3,114,076

FLUORESCENT LAMP CIRCUIT AND STARTING MEANS THEREFOR Filed Aug. 15, 1961 ZSheets-Sheet 1 INVENTOR Dec. 10, 1963 Filed Aug. 15, 1961 TAKIZO KOBAYASHI 3,114,076

FLUORESCENT LAMP CIRCUIT AND STARTING MEANS THEREFOR United States Patent 3,114,076 FLUfiRESCENT LAMP CIRCUIT AND STARTING MEANS THEREFOR Talcizo Kobayashi, 54 Sakane Shimanouchi,

' Kawanishi-shi, Hyogo-iren, Japan Filed Aug. 15, 1961, Ser. No. 131,532 8 Claims. (Cl. 315-190) This invention relates to fluorescent lamps and more specifically to an improved circuit for starting fluorescent lamps utilizing a starting switch and at the same time producing increased light output from the lamp without adversely affecting the normal life of the lamp or the starting switch.

One object of the invention resides in a novel and im proved starting circuit for fluorescent lamps to increase the light output of a fluorescent lamp substantially above its normal light output without diminishing the life of the lamp and at the same time increasing the reliability of the starting circuit by minimizing current flow through the starting switch such as an automatic glow switch or the like.

Another object of the invention resides in a novel and improved lighting circuit for fluorescent lamps that is characterized by its simplicity, reliability and relatively long life.

The above and other objects of the invention will become more apparent from the following description and accompanying drawings forming part of this application.

In the drawings:

FIGURE 1 is a circuit diagram of one embodiment of the invention; and

FIGURES 2 through 7 show modified embodiments of the invention.

A form of the invention illustrated in FIGURE 1 utilizes two inductive units denoted generally by the numerals 1t) and 11. The inductor 16) is. provided with two separate windings 12 and 13, with the winding 12 having a tap 14 thereon. The inductor 11 is also provided with a pair of windings 15 and 16 with the winding 15 tapped at 17. The fluorescent lamp to be energized is generally denoted by the numeral 18 and has a pair of starting filaments 19 and 20. The filament 19 has filament terminals 19a and 1%, while the filament 29 has terminals 20a and .Zlib. For convenience in describing the operation of the circuitry, the portions of coil 12 are denoated by the numerals 12a and 12b,while the portions of the coil 15 are denoted by the numerals 15a and 15b. It is also preferable that the coils 12b, 15b, and 13, 16 have substantially the same impedance, at least during the starting time and these coils are referred to as spot distribution coils. The coil 12 may be referred to as a main, or stabilization coil, while the winding 15a is a starting Winding. The coils 12a, 12b and 13 on inductor are similarly phased and the coils b, 15a and 16 are also arranged for in phase operation.

When an AC. power is applied to the terminals X and Y, energy will flow in the circuit X, coil 12a, tap 14, coils 15b and 15a, the glow switch 21 and coil 16 to terminal Y. This will cause the switch 21 to respond and close the circuit between coils 15a and 16. The filament preheat current will then fiow from terminal X, coils 12a and 1212 through the filament 19, coil 15a, switch 21, the filament and coil 13 to the terminal Y. At the same time current flows through both the filaments 19 and 20, a shunt current will flow in the following circuit; terminal X, coil 12a, coils 15b, 15a, switch 21, coil 16 and thence to the terminal Y. Since the coil 15a is in phase with the coils 15b and 16, the sudden flow of current on starting temporarily increases the impedance of the coils 15b and 16 and thereby reduces the shunt current flowing through these coils to nearly zero. As a result virtually ond path is from terminal X through coil 12a, coil 15b,

filament terminal 1%, filament terminal 20b, coil 16 and thence to terminal Y. This means that arcs are established between each of the terminals of one filament and the corresponding terminal of the other filament to produce substantially increased light output from the fluorescent tube 18.

In the case of a 40-watt fluorescent lamp which is to be lighted by the apparatus described in FIG. 1, the lamp current may be increased to a value at least equaling the rated current for a 60-Watt fluorescent lamp, or about 435 milliamperes. The starting current under these conditions when the glow switch 21 is short circuited, can be easily maintained at or below 700 milliamperes because of the decrease in the shunt current by reason of the effect of the starting coil 15a even through the normal preheating current of a standard 40-watt fluorescent lamp is of the order of 630 milliamperes. 'Because of the relatively low starting current with this invention, the life of the glow switch will be relatively unaffected and its operation will become more reliable. Thus, such difficulties as welding of the contacts of the starting switch through the dissipation of excessive heat and excess arcing are eliminated. Actual tests have indicated that a fluorescent lamp of a given rating can be used to produce a quantity of light corresponding generally to about of its rated output without decreasing lamp life and without in any way adversely affecting the reliability of the apparatus.

The embodiment of the invention illustrated in FIG. 2 corresponds essentially to the structure shown and described in FIG. 1, except that the starting coil 15a forms part of the inductor 19, as shown in FIG. 1. The glow switch 21 in FIG. 2 is connected between the starting coil 15a and the coil 13. This displacement of the glow switch 21 does not affect the operation of the circuit, since the filaments 19 and 2t look into substantially symmetrical circuit arrangements, with the coils 15b and 121) being substantially the same and coils 16 and 13 being substantially the same. Thus, similar operation is effected with the structure shown in FIG. 2 with the glow switch 21 automatically initiating the flow of current to eifect heating of the filaments and the starting Winding 15a reducing the shunt current through the glow switch 21. Thus, it may be seen that the starting coil 15a might form part of either inductor 19 or 11, as may be desired.

FIG. 3 illustrates still another modification of the invention, though it will be observed that while the configuration of the inductors in FIG. 2 appears to differ materiallyfrom the configuration of the inductors of FIGS. 1 and 2, the same beneficial effiects are achieved, namely, reduction of the load on the glow switch and increased light output for the fluorescent 'lamp. In this embodiment of the invention a single magnetic core denoted by the numeral 22 is utilized. The core, which may be of any desired configuration, is illustrated in FIG. 3 as being of a U-s-hape having an upper leg 23, a lower leg 24- and a connecting leg 25. The leg 23 includes a pair of windings 2.6 and 27; the leg 24 includes a pair of windings 28 and 29, while the connecting leg 25 includes a starting winding 30. The glow switch and fluorescent lamp correspond to the switch and lamps of FIGS. 1 and 2 and therefore have been designated b like numerals. The coils 26 and 27 are connected so that when current flows through au os e 03 the coils they will be effectively in phase one with the other and, similarly, coils 28 and 29 are in phase. However, the coils 26 and 27 are out of phase with the coils 28 and 29. Coil 30 is connected in circuit so that it is phased with the coils 23 and 23 and out of phase with coils 26 and 27. l t hen energy is applied to the input terminals X and Y, the current path is from the terminal X through coil 26, filament 19, glow switch 21, starting winding 36*, filament 2t and winding 2'7 to the terminal Y. Thus it is seen that there is essentially the same current flow as was obtained in connection with the circuits of FEGS. l and 2. A second current path will also be formed from terminal X through winding 28, glow switch 21, winding 39 and winding 29 to the terminal Y. This is the shunt path and as a result, the current is again reduced ahnost to zero in the glow switch 21. Upon opening of the glow switch 21 a large current surge is produced through the lamp 1% to efie'ct the establishment of two arcs within the lamp, as for instance, from terminal 19a to tenninal Zita and terminal 1% to terminal 2%, as described in connection with FIG. 1.

MG. 4 illustrates a circuit utilizing two separate inductors, each having a plurality of windings somewhat similar to th inductors of FIGS. 1 and 2, but wherein the starting winding is divided, with a portion of it forming part of one inductor and another portion forming part of the other inductor. In this embodiment of the invention the inductors are denoted by the numerals 3i and 32. Inductor 31 carries windings 33, 34 and a, while inductor 32 carries windings 35, 37 and 35b. The glow switch and the fluorescent lamp are identified by the same numerals used to identify corresponding components in the previous figure. It wiil be observed that the configuration of the circuit shown in FIG. 4 is substantially identical to the circuit shown in FIG. 3 except that the cores of the two inductors are not connected and the winding 34 of HG. 4 is now formed of two separate windings 35a and 3512 on the inductors 31 and 32. It is important that the phase relationship of the coils are maintained as described in connection with FIG. 3, namely, the coil 33 is in phase with the coil 34 and the coil 36 is in phase with the coil 37. The coils 33 and 34, however, are out of phase, with the coils 35 and 37. Since the coils 35a mid 3512 should be in phase one with the other, the coil 35b is therefor phased with the coils 36 and 37 while the coil 35a is out of phase with the coils 33 and 34. The circuit functions in precisely the same manner as described in connection with the circuit of FIG. 3 and consequently further detailed description of the circuit operation to effect the desired results is not deemed necessary.

FIGS. 5, 6 and 7 correspond essentially to the embodiment of the invention shown in FIGS. 1, 2 and 4, except that the windings are arranged on a so-called leakage transformer.

Referring now to FIG. 5, a single inductor 33 is utilized with three loosely coupled cores 39, 4t and 41. Core 39 includes windings 42a, 421); the core 4%) includes a winding 43 land the core 41 includes windings Ma, 44b and 45. The glow switch and fluorescent lamp are identified by the same numerals used to identify corresponding components in the previous figures. Coil 43 open-ates, in effect, as a primary coil which affects the energy. being delivered to the other windings on the inductor 38. The initial starting current flows from the terminal X through "windings 42b and 42a, the filament 19, the winding 4%, glow switch 21, the filament 2t and the winding 42 to the terminal Y. The shunt path includes the terminal X, winding 42b, wind-ing 44a, 44b, the glow switch 2 1 and the winding 45 to the terminal Y. Thus it will be seen that the current flow to energize the filaments of the fluorescent lamp 18 is essentially the same as described in connection with FIG. 1 and the windings 44b and 45 correspond essentially to the starting winding 15a of FIG. 1 and the winding 16. In this way the shunt current reduces the current tlow through the switch, extending its life and at the same time two arcs are formed within the tube 18 'aliording a light output approximately 50 percent greater than the normal light output.

The circuit shown in FIG. 6 is along the lines of the circuit shown in FIG. 5 except that the winding 44]; has been transferred from the core section 41 to the core section 39 and the glow switch 21 is connected between one end of the winding 44b and the winding 42. In all other respects, the circuit functions and operates in the same manner as described in connection with FIG. 5.

The circuit of MG. 7 is also along the lines of the circuit of FIG. 5 except that the winding 4212 on core section 39 of FIG. 5 has been omitted from FIG. 7 and the winding deb on the core section 41 of FIG. 5 is formed of two separate windings, namely, the winding 46 which is formed on the core section 39 and the winding 47 which is formed on the core section 41. The windings are phased in the same manner as described in the previous figures to efiect a reduction of the current through the glow switch 21 on the start and to produce a voltage surge on opening of the glow switch 21 in order to produce two separate iarcs within the lamp 13 and thus produce increased light output without shortening of the life of either the lamp or the glow switch. Thus, a 40-watt lamp, in effect, can be utilized with increased current to produce the light output of, roughly, corresponding to a normal 60-watt fluorescent lamp.

While only certain embodiments of the invention have been illustrated and described, it is evident that modifications, changes and alterations may be made without departing from the hue scope and spirit thereof as defined by the appended claims.

What is claimed is:

1. A starting circuit for a fluorescent lamp having a pair of starting filaments therein, comprising means in cluding at least two magnetically coupled inductive windings each connecting one filament to an electrical energy supply source, a control switch and series connected inductive winding connected between said filaments to produce a heating current through said filaments, and a second inductive circuit including said switch and series connected winding magnetically and electrically coupled to at least one of the first said inductive windings to produce a current through said switch in phase opposition to said heating current, the first said inductive windings have low impedance during starting and upon the opening of said switch produces a current surge through the lamp establishing arc spots on each end of each filament to increase the light output of said lamp and the impedance of said inductive windings is increased.

2. A starting circuit for a fluorescent lamp according to claim 1 wherein said second inductive circuit is serially connected with at least one of said magnetically inductive windings connected with each filament.

3. A starting circuit for a fluorescent lamp having at least two filaments therein comprising inductive means having a main winding and at least two spot distribution windings, second inductive means including at least two spot distribution windings, a starting winding on one of said inductive means, a pair of terminals for application of power to said lamp, a connection between one of said terminals and said main winding, a connection between said main winding and one spot distribution coil on each inductive means, connections between the last said spot distribution coils and one of said filaments, a connection between said other terminal and the other spot distribution coil on each of said inductive means, connections between the last said spot distribution coils and the other of said filaments, a starting switch, a connection between said starting coil and said switch to form a series circuit, and connections between said series circuit and a spot distribution coil connected with each of said filaments, said spot distribution coils having low impedance during starting and increased impedance during operation.

4. A starting circuit for a fluorescent lamp having at least two filaments therein comprising a pair of inductors each having at least two spot distribution windings, a starting winding inductively coupled to at least one of said inductors, a pair of terminals for application of energy to said lamp, a connection between one of said terminals and a spot distribution coil on each of said inductors, connections between each of the last said spot distribution coils and one of said filaments, a connection between the other terminal and the other spot distribution coils, connections between the last said coils and the other of said filaments, a starting switch serially connected with said starting winding to form a serially connected circuit, and connections between said serially connected circuit and each of said filaments, said spot distribution coils having low impedance during starting and increased impedance during operation.

5. A starting circuit according to claim 4 wherein said starting winding is formed of coils Wound on each of said inductors.

6. A starting circuit according to claim 3 wherein said terminals whereby the windings on said inductors are electrically and magnetically coupled to said primary winding.

7. A starting circuit according to claim 4 wherein said inductors form part of a leakage transformer, and said transformer includes a primary winding connected to said terminals whereby the windings on said inductors are electrically and magnetically coupled to said primary winding.

8. A starting circuit according to claim 4 wherein said inductors form part of a leakage transformer, and said transformer includes a primary winding connected to said terminals whereby the windings on said inductors are electrically and magnetically coupled to said primary winding.

References Cited in the file of this patent UNITED STATES PATENTS 2,270,368 Zecher Jan. 20, 1942 FOREIGN PATENTS 853,131 Great Britain Nov. 2, 1960 879,435 Great Britain Oct. 11, 1961 1,074,753 Germany Feb. 4, 1960 

1. A STARTING CIRCUIT FOR A FLUORESCENT LAMP HAVING A PAIR OF STARTING FILAMENTS THEREIN, COMPRISING MEANS INCLUDING AT LEAST TWO MAGNETICALLY COUPLED INDUCTIVE WINDINGS EACH CONNECTING ONE FILAMENT TO AN ELECTRICAL ENERGY SUPPLY SOURCE, A CONTROL SWITCH AND SERIES CONNECTED INDUCTIVE WINDING CONNECTED BETWEEN SAID FILAMENTS TO PRODUCE A HEATING CURRENT THROUGH SAID FILAMENTS, AND A SECOND INDUCTIVE CIRCUIT INCLUDING SAID SWITCH AND SERIES CONNECTED WINDING MAGNETICALLY AND ELECTRICALLY COUPLED TO AT LEAST ONE OF THE FIRST SAID INDUCTIVE WINDINGS TO PRODUCE A CURRENT THROUGH SAID SWITCH IN PHASE OPPOSITION TO SAID HEATING CURRENT, THE FIRST SAID INDUCTIVE WINDINGS HAVE LOW IMPEDANCE DURING STARTING AND UPON THE OPENING OF SAID SWITCH PRODUCES A CURRENT SURGE THROUGH THE LAMP ESTABLISHING ARC SPOTS ON EACH END OF EACH FILAMENT TO INCREASE THE LIGHT OUTPUT OF SAID LAMP AND THE IMPEDANCE OF SAID INDUCTIVE WINDINGS IS INCREASED. 